Field of the Invention
The present invention generally relates to a vehicle air conditioning system. More particularly, the present invention relates to a vehicle air conditioning system that can perform heating and dehumidifying while reducing electric power consumption.
Background Information
Vehicle air conditioning systems are known in the art. A conventional vehicle air conditioning system can operate to condition air inside a vehicle cabin without using engine coolant. When such a system is operated in a heating mode, the system typically uses hot fluid or heated air that has been heated by an electric heater or a combustion heater. The system could also use heat that is extracted by a heat pump from air outside of the vehicle.
Since an electric vehicle does not have a combustion engine, the air conditioning system is unable to use heat that would be discharged from a combustion engine. Thus, an air conditioning system in an electric vehicle can use an electric heater. Since the amount of electric power consumed by an electric heater affects a distance that the vehicle can travel without recharging its battery, the distance typically declines in the winter and other times when the electric power consumption of the electric heater is large. Therefore, a system described in Japanese Patent No. 3477868 is configured to use heat of condensation discharged from a refrigerant-fluid heat exchanger during a heating mode in order to reduce electric power consumption.